List all calendars in the authenticated iCloud account.

Returns each calendar's display name, URL (used as a stable identifier), color, and timezone if available.

Use this when:

• The user asks "what calendars do I have"

• You need a calendar identifier to pass to other tools

• Disambiguating between calendars with similar names

List events from a specific calendar within a time range.

Args:

• calendar: Display name (e.g. "Work") or full CalDAV URL

• start: ISO 8601 datetime for range start

• end: ISO 8601 datetime for range end

Returns an array of events with uid, summary, start, end, location, description, allDay flag. The 'uid' is the stable identifier — use it for update/delete operations.

Create a new event on the specified calendar.

Args:

• calendar: Display name or full CalDAV URL

• summary: Event title (required)

• start, end: ISO 8601 datetimes

• description, location: optional

• allDay: boolean (default false)

Returns the created event's uid and CalDAV URL.

Update fields on an existing event by UID.

Args:

• calendar: Display name or full CalDAV URL where the event lives

• uid: Event UID (from icloud_list_events)

• Any of: summary, description, location, start, end, allDay (only provided fields are updated)

Returns confirmation with the updated UID.

Delete an event by UID.

Args:

• calendar: Display name or full CalDAV URL

• uid: Event UID

This is destructive. Confirm with the user before invoking.